Conventional hose structures for fluid transfer applications (fluid handling hoses) are typically constructed as having a tubular core for transferring fluids. The tubular core is often surrounded by one or more reinforcement layers, which are in turn protected by a surrounding outer sheath or cover. The cover typically protects the core tube from external conditions and provides the hose with some degree of abrasion resistance. The cover may be made from the same or different materials as the core tube. In normal use, fluid handling hoses are used in a variety of applications and may be exposed to a variety of environmental factors and mechanical stresses that cannot always be predicted. It is desirable for the hose to have a strong mechanical integrity to withstand both the internal and external mechanical stresses placed on the hose during use. It is also desirable, in many circumstances, for the hose to be flexible but, at the same time, not prone to kinking. Flexibility is often desirable to facilitate handling of the hose by an operator during use and for storing and/or transporting the hose.
Hoses may be used, for example, for delivering fluids to subterranean structures or environments. As a particular example, fluid handling hoses are employed in surface mining operations to deliver fluids to holes located just beneath the earth's surface. Surface mining involves mining material from the earth's surface rather than in a mine tunnel. Typically, a surface mining operation involves drilling one or more bore holes into the ground or surface to be mined, filling the bore holes with a liquid explosive, and blasting the material so as to break the surface and area surrounding the bore hole into smaller pieces that can be removed from the mining site. A single hose is used to convey the explosive and facilitate filling the bore hole(s). The hose is typically connected to a reel-up device for inserting and removing the hose from a bore hole. Therefore, hoses for such operations should be relatively flexible for handling the hose. Additionally, it is desirable for the hose to have a relatively smooth outer surface so that the hose does not catch or snag the surface as the hose is being inserted into, or more particularly, as it is being removed from the bore hole.
In some situations, it may be desirable to provide an explosion having a force greater than the force obtained from the explosive material alone. A secondary material or catalyst may be added to the primary explosive material to provide a stronger explosion. Depending on the reactivity of the primary explosive material and the catalyst, the secondary material or catalyst typically cannot be mixed or combined with the explosive until just a short time prior to the explosion. The secondary material or catalyst may be added while filling the bore hole with the explosive, but must be added as the hose conveying the explosive material is being pulled out of the bore hole. Thus, a second hose is required for separately transferring or conveying the secondary material or catalyst to the bore hole. This may require additional operators to handle the separate hoses.